I/O Device Guide Introduction to I/O Introduction Overview of I/O Commands OPEN Command USE Command READ Command WRITE Command CLOSE Command Principal Device, Current Device, and Null Device One Process Owns a Device Each Process has a Principal Device InterSystems IRIS Directs I/O Commands to the Current Device When Your Principal Device Becomes Your Current Device Explicitly Using the Principal Device Options for Working with the Principal Device The Null Device Specifying Devices in I/O Commands Specifying Terminals and Printers by Device Name Specifying Devices by InterSystems IRIS ID Specifying Files on Disk Local Interprocess Communication (Pipes) Introduction Opening Pipes to InterSystems IRIS Utilities Pipes and Command Pipes OPEN Command for Interprocess Communication READ Command for Interprocess Communication CPIPE Exit Codes CLOSE Command for Interprocess Communication Using Named Pipes to Communicate with Visual Basic See Also Communication Between InterSystems IRIS Processes Introduction Specifying Memory Buffers for Interjob Communication Devices Interjob Communication Device Numbers I/O Commands for IJC Devices See Also TCP Client/Server Communication Introduction OPEN Command for TCP Devices Current TCP Device USE Command for TCP Devices READ Command for TCP Devices WRITE Command for TCP Devices Closing the Connection See Also TCP Advanced Topics Connection Management Concatenation of Records Multiplexing InterSystems IRIS TCP Devices See Also UDP Client/Server Communication Introduction Establishing a UDP Socket The Host Address IPv4 and IPv6 See Also Terminal I/O Overview Special Variables Show I/O Conditions OPEN and USE Commands READ Command WRITE Command CLOSE Command Predefined Mnemonic Spaces for Terminals PRINT and ZPRINT Commands Programming Your Terminal File I/O Introduction Specifying a File OPEN Command USE Command READ Command WRITE Command CLOSE Command Spool Device Introduction Opening and Using the Spool Device Spooling and Special Variables Closing the Spool Device Viewing the ^SPOOL Global Opening the Spooler Using the %IS Utility Managing Spooled Documents Using %SPOOL Printers Overview of Printers Specifying a Printer Directing Output to a Printer Printer as Alternate Device Controlling Devices with Mnemonic Spaces Predefined Mnemonic Spaces Setting Up Default Mnemonic Spaces Creating a Mnemonic Space Select a Mnemonic Space Managing Devices and Mnemonic Spaces Device Management Utilities Default Devices Identifying Devices Defining Devices Accessing Devices Defining Default Mnemonic Spaces Using ^%IS How ^%IS Works ^%IS Mnemonics Structure of ^%IS Global Device Special Variables